1. Field
The disclosed technology relates to the semiconductor field, and particularly, to semiconductor devices integrating Metal Oxide Semiconductor Field Effect Transistor (MOSFET) having different gate lengths and methods for manufacturing the same.
2. Description of the Related Technology
With continuous scaling down of semiconductor devices, short channel effects are becoming more significant. Thus, a gate stack configuration comprising a high-K gate dielectric and a metal gate conductor is proposed. To avoid degradation of the gate stack, semiconductor devices with such a gate stack configuration are manufactured generally by means of the replacement gate process. The replacement gate process involves forming the high-K gate dielectric and the metal gate conductor in a gap defined between gate spacers. However, it is becoming more and more difficult to form the high-K dielectric and the metal gate conductor in the small gate opening due to the scaling down of the semiconductor devices.
Thus, it is desirable to a method for manufacturing and integrating a MOSFET with a small gate size. It is more desirable to a method for integrating MOSFETs having different gate lengths in one semiconductor substrate.